Portable cofferdam



FIG. 1 is a left perspective view of a portable cofferdam showing our new design;

FIG. 2 is a right perspective view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a left view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof.

The broken line portions of the drawings are included to show unclaimed subject matter and form no part of the claimed design. 

CLAIM The ornamental design for a portable cofferdam, as shown and described. 